I always find that my desk has a lot of stuff on it that I don't really need. I was thinking of getting a shelf for all that stuff, but then I noticed the bulletin board behind by desk, and decided to build a shelf which can be attached to the bulletin board. And since I didn't have any wood, I decided to make mine out of cardboard.

In this Instructable, I'll show you how to make a shelf which can be attached to any wooden or bulletin board surface and which can hold almost 2 kilograms of supplies. And all you need is some cardboard and some hot glue.

## Step 1: Materials

For this project, you will need the following materials:

• A 30-cm scale
• Scissors
• A box cutter or blade
• A pencil or pen
• A protractor
• A hot glue gun
• A large piece of cardboard (I used an old Amazon shipping box)

Make sure that the cardboard is a bit thick, like the ones used for packaging washing machines, TVs, etc.

## Step 2: Template

My bulletin board is around 44-45 cm wide, so i made my template to be around the same length. The shelf is shaped kind of like a stealth plane, with a pointed end and many angles. I designed it like this because I have some smaller circular shelves next to the desk (which are now overflowing) and I wanted my shelf to complement them. I made the shelf around 17 cm long, so that it wouldn't stick out over my head.

The whole template is around 44 cm long and 17 cm wide, though you can modify this to suit your needs. I have noted the lengths of the various lines in the base template in the image. The midpoint referred to in the image is 22 cm.

The supports for this shelf will come from three half-cones (by half-cone, I mean a cone which has been divided vertically), the radii of which are below. I have marked their positions on the template image.

• The left-most and right-most half-cones will be of equal radius, that is 5 cm
• The middle half-cone is the largest and will sit on the midpoint. It will have a radius of 11 cm.

A pair of scissors and a box cutter or blade will be of great help in cutting out the base template.

## Step 3: Making the Supporting Cones

The half-cones for this shelf have also been made out of cardboard. The slant height of the cone must be more than the radii of the semicircles which you have drawn on the template. The angle which you have to cut can be calculated using the following formula:

Angle = (circumference of half-cone * 360 degrees) / (2 * pi * slant height chosen for the cone)

With this angle and the radius you have chosen, cut out the following sector of the circle. In my version, the outer cones should have a radius of 5 cm. I want the cones to be have a slant height of 8 cm, so I used the formula as given. I also made two of them as I wanted

Angle = 5pi cm * 360 degrees / 16pi cm = 112.5 degrees.

Similarly, for the large cone in the middle whose radius is 11 cm, I wanted its cone to be 12 cm, so the angle came out to be 165 degrees.

When you have the sectors ready, take a scale and then, keeping one end on the center of the sector, begin folding the sector into smaller sections as shown in the images. This will help in bending the sector into a half-cone.

## Step 4: Putting the Base Together

When you have your half-cones ready, grab your glue gun and then slowly glue each of the cones to their respective positions as marked by you on the template. Make sure to stay within the boundaries of the semicircles you have drawn (Preferably, the edge of the half-cone should be flush with the semicircle). Repeat this process for all the half-cones you have made.

Try to get the half-cones to be as perpendicular to the base template as you can get them. This will help in increasing the stability of the shelf.

Use liberal amounts of hot glue to hold the half-cones to the template. Make sure that all gaps are filled up and that the half-cones are rigidly held. This will increase the shelf's durability.

In the end, you should have something like what I have shown in the pictures above, with all the half-cones lined up with each other and perpendicular to the template.

## Step 5: Attaching the Back-plate to the Shelf

This is the step in which the whole shelf comes together. You will need another piece of cardboard at least as wide as your shelf is to act as the back panel for the shelf. The whole shelf will be perpendicular to the back-plate as shown.

First, apply some hot glue to the edge of the base and then place it carefully on the back-plate, making sure that it is as straight as possible.

Next, attach half-the cones to the back-plate. Being perpendicular to the base, they should have no problem sitting flush with the back-plate. Use liberal amounts of hot glue to secure the half-cones to the back-plate as they will be doing most of the load-bearing. Apply some hot glue to the top side of the base too.

When you are confident that the shelf is secured firmly to the back-plate, draw a rectangle around the shelf, maybe around 5-7 cm from the top, and cut it out, leaving you with a nice, clean rectangular back-plate upon which the shelf is attached.

This marks the completion of the shelf! Now, the only thing remaining is to attach the shelf to your desired location.

## Step 6: Attaching the Shelf to the Wall/bulletin Board

Finally, the time has come to attach the completed shelf to a wall or bulletin board. Since I have a board in front of my desk, I am going to attach the shelf to the board. However, if you do not, I imagine that you could attach the board to a wooden surface by driving nails through the cardboard back-plate and then the wood.

For attaching the a bulletin board, take around 8-10 thumb tacks (more's the better) and then, holding the shelf flush with the bulletin board, push around 5-7 of them into the top-side of the back-plate (above the shelf's surface), taking care to position them at regular intervals. Push the remaining into the bottom-side of the back-plate, again making sure that they are space regularly.

## Step 7: Putting Something on It

Begin loading items slowly onto the shelf. Keep one item, then leave it there for a while until you are sure that the shelf can hold it, then load the next. As this shelf is made out of cardboard and hot glue secured with thumb tacks, it is unlikely to be able to carry more than 2 kilograms. I did manage to balance a 2 kilogram dumbbell on it for a few minutes, but it looked quite unstable. However, it is holding all the paraphernalia I have kept on it until now very well!

So that was it! I hope you all enjoyed my project. If any of you make it, I would like to see it in the comments!

PS. If any of you try this with wood, it might be able to hold more weight. Additionally, the size and diameters of the half-cones I used are probably not the best at supporting the shelf. I urge you to experiment with different radii, lengths, etc. to find the optimum results.

<p>you could always brush a few coats fiberglass resin on it (no need for the fiberglass mat) and fill the exposed corrugated edges with bondo; then paint it. <br><br>it would make it sturdier and not look like it's made out of cardboard.</p>
<p>That's a great idea. I was planning on painting it one of these days :)</p>
<p>That came out really well :) The cones are a good idea to reinforce it. </p>
<p>Thanks a lot!</p>